Junctions involving electrical wiring harnesses should be sealed or protected against exposure to the elements, particularly moisture: to inhibit corrosion; to reduce the likelihood of electrical shorts; and, to otherwise enhance performance of the electrical system of concern. Generally, such junctions involve at least two, and often a larger number, of insulated wires brought together, and the ends are exposed and joined at a particular junction as by clamping and/or the use of welds or soldering. Numerous seals and seal methods have been developed to protect the junctions; however, none have been completely satisfactory.
An early, convenient and still frequently used method of providing a protective seal around a wire junction is through a wrapping of an electrically insulative adhesive tape around the connection or junction. This method is inexpensive and easy to apply. However, it is not very effective in providing for a good moisture seal.
A relatively recently developed alternative is the use of a sealant pad having a rectangular shape comprising a substrate upon which is positioned a relatively thick pad of a tacky sealant material. This pad is folded about the splice or junction such that the sealant surfaces come in contact. Then the splice and the sealant pad are placed in the center of a compression tool with the seam up and pressure is applied to the pad to further compress the sealant about the junction and the wire ends. U.S. application, Ser. No. 130,541 filed Dec. 9, 1987 and assigned to the assignee of this application discloses a sealant pad as described and the method of making the seal. This application and the disclosure is incorporated herein by reference. The sealant pad illustrated in FIG. 6 of the above identified application has a pad of sealant material positioned asymmetrically on a substrate such that the substrate projects beyond several edges of the pad. One edge provided a flap at a seam and the other two edges provided space to permit expansion of the sealant when pressure was applied.
The sealant as the pad is being deformed and the sealant is forced to flow around the wires and splice, is usually squeezed from the seam and the ends of the folded substrate.
What has been lacking is a way to keep the seam of the sealant pad secure when the junction and the pad are placed in the press.
The present invention reduces this problem and also serves to provide an insulated seal about the junction which has a better appearance.
The present invention provides a sealant pad which has a length of pressure sensitive adhesive tape extending beyond at least one edge of the sealant to maintain a closed seam and restrict sealant from flowing out of a seam as the pad is formed about the junction or splice.